Intermodal shipping containers are large (8 feet by 8 feet by 40 feet is one typical size) and, when loaded, may weigh several tons. Such shipping containers must often be transferred to and from transport vehicles, such as vessels, truck trailers, and railroad cars. In some configurations, automatic latching mechanisms are installed in the corners of vessels, truck trailers, or railroad cars designed to transport intermodal shipping containers. These latching mechanisms can include a spring-loaded latch member which is adapted to engage a latching receptacle provided on the corresponding corners of a shipping container. The shipping containers are typically transferred to and from the vessel, truck trailer, or railroad car by large cranes.
Intermodal shipping containers, as used herein, refer to those that conform to International Standardization Organization (ISO) container manufacturing standards. In general, the intermodal shipping containers can be, for example, general purpose or dry, insulated, flat rack or platform, open top, refrigerated, or tank. General purpose containers, also referred to as cube containers, are enclosed, box-type containers used for general-purpose transportation. Cargo is typically loaded from one or both ends of the container. Insulated or thermal containers, with insulated walls but no refrigeration unit, are often used to transport chilled and frozen goods as well as temperature sensitive materials and products. Intermodal shipping containers also come in many other configurations, e.g., with one or more end and/or side doors and/or specially reinforced floors and/or frames for extra heavy loading. Generally, common container lengths used in international commerce include 20′, 28′, 40′ and 48′ as well as other sizes such as 10′, 24′, 44′, 45′, 46′, 53′, and 56′. Typical container height is 8′6″ or 9′6″ for high cube or extended height containers. The standard width for containers is 8′. Various other combinations of lengths, widths, and/or heights may also be employed. The containers may be made of, for example, steel, aluminum, or the like. Typically, because of weight constraints such as maximum load limits on highways, high density or heavy goods may be loaded in shorter containers. For example, a 40′ container can have a typical container rating of approximately 67,000 pounds. Intermodal shipping containers generally have fittings on the top and bottom which facilitate in their handling and that enable them to be stacked in terminals, on ships, and/or in operation. The fittings primarily include oval-shaped holes at the lift points. For transport, storage or operation, containers may be stacked and connected to each other with interbox connectors (IBCs), i.e., pieces of hardware that fit into the oval holes of the containers above and below and are turned to lock the two containers together.